1. Field of the Invention
The present invention relates generally to an organic light emitting diode (OLED) display. More particularly, the present invention relates to an OLED display which prevents ink from crossing over a barrier rib and flowing into a neighboring pixel without a hydrophobic surface treatment to the barrier rib.
2. Description of the Related Art
An organic light emitting diode (OLED) display includes two electrodes and an organic emission layer disposed between the two electrodes, and electrons injected from one electrode and holes injected from the other electrode are combined in the organic emission layer so that excitons are formed, and light is emitted by energy generated from the excitons.
Among them, the organic emission layer is formed by using a nozzle coating method or an inkjet printing method. In this case, a problem may be generated in that ink dripped to the pixel enclosed by a barrier rib through the inkjet printing method passes over the barrier rib and flows into a neighboring pixel. To prevent this problem, plasma treatment is performed on the surface of the barrier rib to provide hydrophobicity to the surface of the barrier rib. Accordingly, the hydrophilic ink does not pass over the barrier rib which has undergone the hydrophobic surface treatment.
However, when the barrier rib surface has hydrophobicity, the side portion of the barrier rib, as well as the upper portion of the barrier rib, has hydrophobicity so that the ink is not coated on the side portion of the barrier rib. As a result, the thickness is different between the edge of the pixel and the center thereof and, as a result, the surface of the pixel is not flat. Therefore, light leakage is generated at the edge of the pixel, and thereby the color reproducibility is decreased due to the difference of the color between the edge of the pixel and the center thereof.
The above information disclosed in this Background section is only for enhancement of an understanding of the background of the described technology, and therefore it may contain information which does not form the prior art which is already known in this country to a person of ordinary skill in the art.